Music producing apparatus



' MUSIC PRODUCING APPARATUS Filed July 26, 1937 Patented Jan. 14, 1941 UNITED STATES PATENT OFFICE 17 Claims.

The present invention relates generally toA apparatus for producing music. More particularly the invention relates to that type of'music producing apparatus which is adapted for use in connection with an electrical amplifier device for translating into sound, electric impulses or oscillatory variations and comprises as the main or essential parts thereof: (l) a tuned vibrator such as a string; (2) a pair of condenser type electrodes `which are adapted tohave an electric capacity maintained therebetween as the result of one being at ground potential and the other being supplied with high voltage current through a resistor andare further adapted to have electrical impulses or oscillatory variations set up across the capacity as the result of vibration of the vibrator; and (3) conductor means for transmitting the electrical impulses or oscillatory variations to the amplifier device for translation into sound.

One object of the invention is to provide a music producing apparatus of this type which is simpler in design and construction and produces music of better tone quality than previously .designed apparatus of the same general character and for the same purpose by reason of the fact y that the electrode at ground potential is separated from the other electrode by a resilient dielectric and the vibrator is applied directly to the grounded electrode and operates in response to vibration thereof to vibrate the grounded electrode and thus set up the desired electrical impulses or oscillatory variations for translation by the amplifier device into sound.

Another object of the invention is to provide a music producing apparatus of this type in which the electrical capacity between the condenser type electrodes together with the intensity of the electrical impulses is increased by way of a pair of U-shaped interleaved metallic sheets which contact respectively with the two electrodes.

A further object of the invention is to provide a music producing apparatus of the type under consideration which is especially adapted for embodiment in a guitar or like string instrument byvhaving the electrode at ground potential form the bridge for the strings oi the guitar.

A still further object of the invention is to provide a music producing apparatus which is generally of new and improved design and may be manufactured at a low and reasonable cost.

Other objects of the invention and the various advantages and characteristics of the present music producing apparatus will be apparent from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawing which accompanies and forms a part of this specification or disclosure and in which like numerals of'reference' denote corresponding parts throughout the several views:

Figure 1 is a plan view of a guitar type music producing apparatus embodying the invention;

Figure 2 is a fragmentary bottom view of the body of the guitar showing in detail certain of the electrical connections and parts of the ampliiler device for transmitting into sound, electrical impulses emanating from the electrode at high potential in response to vibration of the strings on the bridge type grounded electrode;

Figure 3 is an enlarged vertical longitudinal sectional view taken on the line 3--3 of Figure 1 and illustrating in detail the constructionv and arrangement of the two electrodes;

Figure 4 is an enlarged vertical transverse sectional view taken on the line 4-4 of Figure 3 25 and showing the specific design of the grounded electrode which serves as the bridge for the strings of the guitar; and

Figure 5 is a diagrammatic view of the amplifier device showing the manner in which the same is connected to the two electrodes so as to receive electrical impulses or oscillatory variations therefrom.

The music producing apparatus which is shown in the drawing constitutes one embodiment of the 3 invention and comprises a guitar 6, a pair of electrodes l and 8 for setting up electrical impulses during playing of the guitar and an amplifier device 9 lor translating the electrical impulses into sound. A

The guitar 6 comprises a body I0, a neck li, a tuning head i2, a set of parallelly arranged, laterally spaced, differently tuned strings I3, and is of the type that embodies no sound box. The r body, neck and tuning head are in the form of 4" a one-piece casting and are hence rigidly connected together. The body i0 embodies a'substantially circular top wall I4 and a downwardly and outwardly extending marginal flange I5. The latter is formed integrally with the top wall and defines with the latter a compartment I6 which is normally closed by a sheet metal plate I1. The latter, as shown in Figure 2, is positioned substantially flush with the outwardly extending portion of the iiange I5 and is removably securedv 5 in place by means of screws I8 which fit within internally threaded sockets in bosses I9 on the inner face of the downwardly extending portion of the flange I5. 'Ihe top wall I4 of the body of the guitar' is iiush with the neck IIl and has an integral extension 28 directly opposite to the neck. The neck has anger board 2I in the top face thereof and underlies the strings I3, as shown in Figure 1. The tuning head I2 is located at the outer end of the neck II and embodies a plurality of winding spindles 22. The

strings 'are connectedvat one end thereof to the` winding spindles 22 and extend longitudinally of the neck 2| and across the top wall I4 oi the body I8. at the other end of the guitar the strings I3 extend through holes 23 in the extension 20 to pins 24 which underlie the extension and serve to anchor the strings in place. A bar 25 and a spacing nut 28 serve to hold the strings in spaced relation with the top wall I4 of the guitar body and the finger board 2l of the neck Il. The bar 25 is located in close proximity to the holes 23 and the spacing nut 26 is disposed between the contiguous ends of the neck and tuning head. By turning the spindles 22 the strings may be tightened or loosened for tuning purposes as Well y understood in the art. The strings i3 serve as vibrators and when plucked in connection with playing oi the guitar set up mechanical vibrations.

The electrodes 1 and 8 are associated with a one-piece metallic elongated housing 21 and operate in response to vibration of the strings. as

hereinafter described, to set up electrical impulses which are transmitted to the amplifier device 9 and are translated by the latter into musical sound. The housing 21 extends transversely across the top face of the top Wall i4 of the guitar body and consists of a top 28, a pair of side walls 23, and a pair of end walls38. It underlies the strings and is removably secured in close proximity' to the string spacing bar 25 by a pair of screws 3 I The latter extend through holes 32 in the wall I4 of the guitar body'and project into internally threaded sockets in the end walls 38 of the housing 21.1` The side walls 29 of the housing extend between the end walls and together with the top wall 28 denne an elongated chamber 33. The housing 21 extends substantially parallel to the bar 28 and is of such height that the top Wall 28 thereof underlies and is spaced a small distance beneath the overlying portions of the strings I3.

The electrode 1 forms the bridge for the guitar 6. It is in the form of an inverted T as tar as cross-section is concerned, and consists of an upstanding web 34 and a horizontal web 35. The two webs are conterminous and are formed integrally with one another. The electrode 1 is preferably formed of aluminum or like metal and is grounded to the metallic body I8 of the guitar by way of the strings I3. It is understood that the metallic body I0 of the instrument exists at ground potential or a reference potentian corresponding to the body potential of the player. The horizontal web 35 is disposed in the upper portion of the chamber 33 and underlies an elongated strip 38 of rubber or like resillent elastic material. 'The strip 38 fits against the inner face of the top7 28 of the housing 21 and has a longitudinal slot 31 through which extends the upstanding web 34 of the electrode 1. Said web 34 projects upwards through a longitudinal slot 38 in the top 28 of the housing 21 and has string receiving notches 39 in the top face thereof. The slot 38 in the top 28 of the housing is' slightly longer and wider than the web 34 with the result that the electrode 1 is free to vibrate in response to vibration of the strings I3 in connection with playing of the guitar. The slot 31 is the same in length and width as the upstanding web 34 of the electrode 1 and is so positioned with respect to the top 28 of the housing that it holds or maintains the web 34 in centered relation with the slot 38, as shown in Figures 3 and 4.

The electrode 8 is in the form of a iiat plate of brass or like metal and isf/held in a socket 48 in a block 4I o1' insulating material so that it underlies and is spaced beneath the horizontal web 35 of the electrode 1. The block 4I is disposed in the lower portion of the chamber 33 in theV housing 21 and rests on the top face of the top wall I4 of the guitar body I0. The socket 40 is formed in the top portion of the block 4I tance of the condenser in accordance with the frequency and mode of vibration of the strings. The` block 4I serves to insulate the electrode 8 from the metallic housing 21 and also the metallic bcdy of the guitar.

In order to increase the electrical capacity between the two electrodes 1 and 8 and also increase the output of the electrodes, that is, the intensity of the current impulses emanating from the electrode 8 during playing of the guitar, two U- shaped sheets 43 and 44 are provided. These sheets. are formed of brass or like conductor material and extend between the electrodes 1 and 8. The sheet 43 comprises a top-piece 45 and a bottom piece 48 which extend lengthwise of and substantially correspond in size to the horizontal web 35 of the electrode 1. The top piece 45 of the brass sheet 43 abuts against the bottom face of the web 35, as shown in Figures 3 and 4, and is connected at one end thereof to the adjoining end of the bottom piece 46 by a substantially semi-cylindrical bend 41. The sheet 44 is arranged in interleaved relation with the sheet 43 and consists of a top piece 48 and a bottom piece 49. These two last mentioned pieces correspond in size to the high voltage electrode 8 and are connected together by a bend 50. The top piece 48 fits between and is spaced from the top and bottom pieces 45 and 48 of the sheet 43 and the bottom piece 48 is spaced beneath the bottom piece 48 of the sheet 43 and rests on and contacts electrically with the electrode 8. An S- pieces oi the sheets so as to insulate the sheet 43 from the sheet 44. By reason of the fact that the strip 5I is formed of elastic material, the grounded electrode 1 is not restricted by the electrode 8, as far as vibratory movement thereof is concerned. The sheets 43 and 44 are spaced from the side and end walls o! the housing 21 and henpe are insulated therefrom.

The amplifier device 9 is of conventional or standard design and includes a thermionic vacuum tube 52, a high voltage conductor 53, a resistor 54, a potentiometer 55, and a condenser 5l. The tube 52 with its associated circuits and v'Inerating parts, is enclosed in an independent or separate casing (not shown), whereas the resistor 54, the potentiometer 55 and the condenser 58 are associated with the guitar and are disposed in the compartment I5 between the plate I1 and the top wall I4 of the guitar body. The conductor 53 receives high voltage current from a suitable source (not shown? and includes a section 5 3* and a section 5l. The section 53h extends between one end of the section 53* and one end oi' the resistor 54 and is disposed in a tube 51 which, as shown in Figure 1, extends through a hole 58 in the rearwardly extending portion of the flange I5 and projects into the compartment i5. 'I'he resistor 54 is mounted in any suitable manner in the compartment I5 'and is connected to the conductor 42. The latter extends through a hole 59 in the top wall I4 of the guitar body and leads from the resistor to the electrode 8. When the apparatus is in operation, high voltage current flows through the conductor 5l to the resistor 54 and thence via the conductor 42 to the electrode 8. As a result of passage or flow of high voltage current to the electrode 8, an electrical capacity is maintained between said electrode 8 and the grounded electrode 1. The resistor 54 prevents charge in the electric capacity from altering rapidly and thus limits the changing of the charge by the vibration oi the electrode 1. The potentiometer 55 is located in the compartment I5 adjacent to the resistor 54 and comprises an arcuate resistance element 55 and a rotatable contact 55h. The rotatable contact is connected by a conductor 50 to the grid oi the thermlonic vacuum tube 52. Said conductor 50 consists of a section Ell leading to the grid and a section 50i which extends between the section Biln and the movable contact 55b and is disposed in the tube 51. One end of the resistance elelnent 55 is connected by a conductor 5I to one plate of the'condenser 55 and the other en'd of the element is connected to a ground Wire 52. 'I'he other plate of the condenser 58 is connected by a conductor 53 to the conductor 42 between the electrode 8 and the resistor 54. The ground wire 62 comprises a section 52* and a section 62h. The section 62' is included and forms a part of the circuit for the cathode of the thermionic vacuum tube 52 and the section 62b leads from the section 62'- to the resistance element 55u of the potentiometer and is disposed in the tube 51. The end of the tube 51 which is remote from the guitar body is provided with a three contact plug (not shown) which is adapted for insertion in a three contact Isocllzet (also not shown) and serves to join the conductor sections 53h, Bilb and 62b to the conductor sections 53e, 60e and 62a, respectively. The electrical impulses or oscillatory variations resulting from vibration of the electrode 1 by the strings i3 pass, by way .of the conductor 53, to the condenser 55, which, as shown in Figure 2, is mounted in the compartment l5 in prordmity to the resistor 54 and the potentiometer 55. From the condenser 56 the electrical impulses are transmitted via the potentiometer and are adapted so to control. the tube 52 that the latter together with the other parts of the amplier device translate them into musical sound effects. The potentiometer 55 serves as a volume control for the amplifier device 9 and may be adjusted by rotating the contact 55h. The latter, as shown in Figures 1 and 2, is mounted on an insulated rod 54 which extends through the top Wall I4 of the guitar body and is provided with a turning knob 85.

When the apparatus is in operation and the strings I3 of the guitar are plucked in connection with the rendition or playing of a musical composition, each of the plucked strings operates to vibrate in a specific manner the electrode 1 and to cause the latter to vary the capacitance of the condenser which variations serve to change the constants of the grid circuit of tube 52 and are translated into sound by the ampliiier device 9. By reason of the fact that the strings il are diilerently tuned there are different sets of current impulses set up as the result of vibration oi the strings and such sets are of diiierent frequency and hence cause the amplifier device to produce different sounds or musical notes.

By reason of the fact that the electrode 1 constitutes or forms the bridge of the guitar the construction of the apparatus as a whole is simplified. Because the U-shaped interleaved plates 43 and 44 are employed between the two electrodes the capacity of the electrical charge between the electrodes is materially increased with the result that the tones or notes emanating from the amplifier device E are clear and sharp.

Whereas the invention has been described in connection with a guitar 5 it is to be understood that it may be embodied or employed in connection with other musical instruments wherein electrical sound reproduction is desired. It is also to be understood that the invention is not to be restricted to the details set forth since these may be modified within the scope of the appended claims, without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

'1. A music producing apparatus adapted for use with an electric amplifier device for translating electrical impulses into sound, and comprising in combination a grounded electrode, a high voltage electrode spaced from the .grounded electrode and forming an electric capacity therebetween, a tuned vibrator connected to one of the electrodes to transmit vibration thereto and adapted when vibrated to set up a varying electrical capacitance between said electrodes, and means for. connecting said electrodes in the circuit of the amplifier device.

2. A music producing apparatus adapted for use with an electric amplifier device for translating electrical impulses into sound, and comprising in combination a vibrator, a grounded electrode having the vibrator applied thereto and adapted to be vibrated by the latter, a high voltage electrode in spaced relation with the grounded electrode and adapted to have a variable capacitance created therebetween in response to vibration of the grounded electrode, and means for connecting said electrodes in the circuit of the amplier device.

3. A music producing apparatus adapted for use with an electric amplifier device for translating electrical impulses into sound, and comprising in combination a string, a grounded elecextending thereacross and adapted to be vibrat ed by the latter, a high voltage electrode in spaced relation with the grounded electrode `forming an electrical capacity-between it and said grounded electrode and adapted in response to vibration of the grounded electrode by the string to have a variable capacitance created therebetween, and means for connecting the said electrodes in the circuit of the amplier device.

4. A music producing apparatus adapted for use with an electric amplifier device lor transuse with an electric amplifier device for trans- Y lating electrical impulses into sound, and comprising in combination a tuned vibrator, a grounded electrode having the vibrator applied thereto and adapted to be vibrated by the latter, a second electrode positioned in spaced relation with the grounded electrode and adapted to have high voltage current supplied thereto whereby the capacity existing between the electrodes is varied in accordance with the vibration of the grounded electrode, a resilient dielectric positioned between the two electrodes and serving to support the grounded electrode so that it is free to vibrate, and means for connecting the said electrodes in the circuit of the ampliiler device.

6. A music producing apparatus adapted for use with an electric ampliiier device for translating electrical impulses' into sound, and comprising in combination a grounded electrode, a high voltage electrode spaced from the grounded electrode and forming an electrical capacity therebetween, means for increasing said capacity comprising a pair ot interleaved U-shaped conductor sheets abutting respectively against the electrodes and having a resilient dielectric therebetween, a tuned vibrator connected to one of the electrodes to transmit vibration thereto whereby the capacitance is varied, and means for connecting the said electrodes in the circuit of the ampliiier device.

'1. A music producing apparatus adapted for use with an electric ampliiler device for translating electrical impulses into sound, and comprising in combination a tuned vibrator,4 a grounded electrode having the vibrator applied thereto and adapted to be vibrated by the latter, a high voltage electrode positioned in spaced relation with the grounded electrode and adapted to have a varying capitance maintained therebetween in responseto vibration of the grounded electrode of the vibrator, means for increasing said capacity comprising a pair oi interleaved U-shaped conductor sheets abutting respectively against the electrodes and having a resilient dielectric therebetween, and means for connecting the electrodes in the circuit of the amplifier device. i

8. A music producing apparatus adapted for use with an electric amplier device for translating electrical impulses into sound, and comprising in combination a plurality oi laterally 'the amplier device.

2,228,881 trode in the form ot s. bridge having the string spaced diilerently tuned strings, a grounded electrode extending transversely across and forming a bridge for said strings adapted to be vibrated by the latter, la high voltage electrode positioned in spaced relation with the grounded electrode 5 and adapted to have a variable capacitance created therebetween in response to vibration oi the grounded electrode by the strings, and means for connecting the said electrodes in the circuit of the amplier device.

9. A music producing apparatus adapted for use with an electric ampliiler device fortranslating electrical impulses into sound, and comprising in combination a plurality of laterally spaced dierently tuned strings, a grounded electrode 15 extending transversely across "and forming a bridge for said strings adaptedvto be vibrated by the latter, a high voltage electrode positioned in spaced relation with the grounded'electrode and adapted to have a varying capacitance created 20 therebetween in response to vibration of the grounded electrode by the strings, a resilient dielectric positioned 'between the two electrodes and serving yieldingly to support .the grounded electrode, and means for connecting the said 25 electrodes in the circuit of the amplifier device.

10. A music producing apparatus adapted for use with an electric ampliier device for translating electrical impulses into sound, and comprising in combination a housing having a chamber 30 therein and a slot leading to said chamber, a grounded electrode having a part thereof yieldingly mounted in the chamber and a rigid part projecting outwards through the slot to the housing exterior, a tuned vibrator applied to said 35 rigid part of the grounded electrode and adapted to vibrate the latter, a high voltage electrode disposed in said chamber in spaced relation with the grounded electrode and adapted to have a variable capacitance created therebetween in response to vibration of the grounded electrode, and conductor means for connecting said electrodes in the circuit of the ampliiier device.

11. A music producing apparatus adapted for use with an electric ampliner device for translating electrical impulses into sound, and comprising in combination a housing having a chamber therein and a slot leading to said chamber. a grounded electrode having one part thereof disposed in the chamber and another part extending loosely through the slot and projecting to the exterior of the housing, a vibrator applied directly to said another part of the grounded electrode and adapted to vibrate the'latter, a high voltage electrode positioned in the chamber in spaced relation with the grounded electrode and adapted to form an electrical capacity between it and said grounded electrode and to have the capacitance varied in response to vibration of the grounded electrode by the vibrator, a resilient dielectric disposed between the two electrodes and serving yieldingly to support the grounded electrode, and conducting means for connecting the said electrodes in the circuit oi 12. A music producing apparatus adapted for use with an electric amplifier device i'or translating electrical impulses into sound, and comprising in combination an elongated housing having a chamber therein and a longitudinally extending slot communicating with the chamber; an elongated grounded electrode of T-shaped cross-section having a web disposed in the chamber and a web at right angles to the nrst mentioned web extending loosely through the slot 76 and forming a bridge. a plurality of laterally spaced diiierently tuned strings supported intermediate oi' their ends by said second mentioned web and adapted in response to vibration thereof 5 to vibrate the/grounded electrode, a high voltage electrode disposed in the chamber o! the housing in spaced relation with said iirst mentioned web and adapted to have a variable capacitance created therebetween in response to vibration of l the grounded electrode by the strings, and means i'or connecting said electrodes in the circuit of the amplifier device.

13. A music producing apparatus adapted for use with an electric amplifier device for trans- 15 lating electrical impulses into sound, andcomprising in combination an elongated housing having a chamber therein and a longitudinally extending slot communicating with the chamber, an l elongated grounded electrode oi T-shaped cross- 20 section having a web disposed in the chamber and a web at right angles to the ilrst mentioned web extending loosely through the slot and forming a bridge, a plurality of laterally spaced differently tuned strings supported intermediate of 25 their ends by said second mentioned web and adapted in response to vibration thereof torvibrate the grounded electrode, a high voltage electrode disposed in the chamber oi the housing in spaced relation with said iirst mentioned 30 web and adapted to have a variable capacitance created therebetween, 'in response to vibration oi the grounded electrode by the strings, a resilient dielectric located between the high volt-` age electrode and said iirst mentioned web of 35 the grounded electrode and serving yieldingly to support said grounded electrode, and means for connecting the said electrodes in the circuit oi' the amplier device'. f

14. A music producing apparatus adapted ior 40 use with an electric amplifier device for `translating electrical impulses into sound, and comprising in combination an elongated housing having a chamber therein and a longitudinally extending slot communicating with the cham- 45 ber, an elongated grounded electrode oi T-shaped K cross-section having a web disposed in the chamber and a web at right angles to the iirst mentioned web extending looselythrough the slot and forming a bridge, a plurality of laterally 50 spaced differently tuned strings supported intermediate oi their ends by said second mentioned web and adapted in response to vibration thereof to vibrate the grounded electrode, a high voltage electrode disposed in the chamber in spaced relation with the rst mentioned web of the grounded electrode and adapted to maintain an electrical capacity between it and said grounded electrode and to have a variable capacitance set up therebetween in response to vibration oi the grounded electrode by the strings, means for increasing said capacity comprising a pair of U- shaped interleaved conductor sheets contacting respectively with the two electrodes and having a resilient dielectric therebetween, and a conductor leading from the housing and. adapted to conduct the impulses from the high tension electrode to said amplifier device.

15. A music producing apparatus adapted for use with an electric ampliiier device for translating electrical impulses into sound comprising in combination a vibrating member, a circuit having a variable condenser and an amplifying device therein connected, said condenser com- .prising a iixed electrode and a movable electrode,

separate interleaved conducting members connected to each o! the said electrodes and positioned between said electrodes.. resilient insulating means separating said members. and a mechanical connection between said vibrating member and said movable electrode whereby the capacitance of the condenser is varied by movement of the said vibrating member.

16. A music producing apparatus adapted for use with an electric ampliiier device for translating electrical impulses into sound comprising in combination a plurality oi vibrating elements.

a circuit having a variable condenser and an amplifying device therein connected, said condenser comprising a nxed electrode and almovable electrode across which the elements are positioned, separate interleaved conducting members connected to each of the said electrodes and positioned therebetween having areas greater than said electrodes and resilient insulating 4 means separating said members.

l'l. A music producing apparatus adapted for use with an electricI amplifier device for trans` lating electrical impulses into sound comprising in combination a vibrating member, a circuit having a variable condenser and an amplifying device therein connected, said condenser comprising a iixed electrode and a movable electrode spaced and electrically insulated from said xed electrode, and a mechanical connection Ibetween said vibrating member and said movable electrode whereby said movable electrode is vibrated by the movement of the said vibrating member.

. .MERWIN 1". LE CLAIR. 

